Palmerston, upon his return to the Foreign Office in the spring of 1835, was struck by the soundness of the Duke's opinion upon the subject of the Dardanelles.[436] Ponsonby was, in consequence, given no further authority over the movements of the Mediterranean squadron. No man at this time was more absolutely persuaded of the Machiavellian character of Russian policy than Lord Ponsonby. Neither words nor deeds could shake his opinion upon that point. Although the Russian envoy at Constantinople had co-operated with his colleagues in preventing a renewal of the struggle between the Sultan and the Pasha, the British ambassador was none the less convinced that Nicholas was secretly scheming to create a pretext for intervention. Again, when M. de Boutenieff assisted him in obtaining redress for the ill-treatment of a British subject at the hands of the Turkish police, he explained his conduct by suggesting that "the Russian minister was perhaps taken by surprise, and that those honourable feelings, which are natural to him, operated upon him."[437] Nor would he allow that the Cabinet of St. Petersburg was actuated either by disinterested or generous motives when, in 1836, it consented to remit some of the indemnity due from Turkey and to evacuate Silistria. That fortress, he declared, was of no value to Russia, and, by relinquishing it, she "would obtain the advantage of making the world believe in her moderation."[438] Being thus convinced that the Tsar and his advisers entertained the most sinister designs against the integrity of the Ottoman Empire, he concluded that a secret understanding must exist between Russia and Mehemet Ali, the powerful and disaffected vassal of the Sultan. The effect of Lord Ponsonby's alarmist despatches was to some extent counteracted by the more statesmanlike reports of Lord Durham, his nephew by marriage. The Duke of Wellington's intention to send an ambassador of St. Petersburg had enabled the Whigs, upon their return to power, to despatch Lord Durham in that capacity to the Russian capital. Durham, during the two years he was in Russia, travelled through the southern provinces and made an exhaustive study of the resources of the country. The result of his observations and enquiries convinced him that Russia's power for offensive war had been greatly exaggerated. Furthermore, he was persuaded that the Tsar Nicholas and almost all intelligent Russians were sincerely desirous of establishing a good understanding with England, and had altogether abandoned the idea of acquiring Constantinople. In short, he saw no reason why "a rival and an enemy should not be converted into a friend and an ally."[439]